Evaluation of the real-time protein adsorption kinetics on albumin-binding surfaces by dynamic in situ spectroscopic ellipsometry

Functionalized surfaces with an affinity for albumin over competing serum proteins were prepared by immobilizing linear peptides or a small chemical ligand (SCL) with albumin-binding properties on silanized silicon surfaces. The real time adsorption of human serum albumin from single- and multi-component systems was monitored by dynamic ellipsometry. The experimentally obtained time-dependent adsorption data were analyzed by two models: a) a pseudo-first-order model and b) a biphasic kinetic model that accounted for the formation of tightly and loosely bound complexes. The biphasic kinetic model better fit the experimental data, and the binding constants were determined by non-linear regression analyses. The net forward rate constant for the tightly bound complex formation was distinctively higher for surfaces functionalized with peptides (∼ 0.014 min ^{- 1}) when compared to surfaces functionalized with SCL (∼ 10 ^{- 3} min ^{- 1}).